Joining In
by StarkLovesShawarma
Summary: Rin and Nitori had managed to keep their sexual endeavors a complete secret from their roommates and teammates thus far, but what happens when Sousuke comes home early one night from weight training? Sousuke/Rin/Nitori. Rated M for sexual content.


**Guys, I'm sorry I keep holding off my Rintori fic but I keep getting stuck at it. Trust me, it's still in the process of being finished, but every time I write another paragraph writer's block hits me hard. Anyway, in the meantime, enjoy this! I've been thinking about a three way (or possibly a four way in the future) of the Samezuka boys for quite some time now. And sorry I get lazy at one point in this. You'll see what I'm talking about when you get to it...not that I think it will matter that much anyway. **

_"Ngh-Ai..." _Rin breathed out through his slightly quivering mouth, his sharp teeth biting down softly on his lower lip to stifle the pleasured moan forming in his throat. His ruby eyes were half lidded, staring down at Nitori, who was currently working his cock with his warm and wet tongue. The silver haired teen bashfully peaked up at his roommate after hearing his name, watching Rin's heated expression as he enclosed his lips around the tip of his erection, swirling his tongue around sensually. Feeling a hot blush begin to creep over his own face, Nitori closed his eyes in embarrassment, bringing his mouth down to engulf Rin's length fully.

This was something the two teammates had participated in only a small number of times, probably less than they could count on one hand. A couple of instances when they were still roommates, and even fewer after Nitori had switched rooms with Sousuke for the new semester. Even though Rin rarely showed it, he admired Nitori and actually found his doting attitude very cute at times. So cute, apparently, that he could no longer take it, and one day ended up making an advance on his younger roommate, who, to the red head's surprise, did not reject it. From then on, the two had managed to keep their sexual endeavors a complete secret from their roommates and team members.

Tonight seemed to be the perfect opportunity for a little get together between Rin and Nitori because Sousuke had told them he was going to stay out late for some extra weight training. Their raven haired teammate rarely stayed after scheduled practice, so Rin had pulled Nitori aside afterward, tugging him along to join him in his room for the evening. It took a few tries to shake the curious and clingy Momotarou from Nitori's arm, the orange haired first year whining and complaining about Nitori leaving him to be lonely in their own room. But, they were successful at getting their privacy, retreating back to Rin's room with no more interruptions.

Now they were in the full swing of things, Rin reclined back on his bed, Nitori nestled between his bent legs, sucking him off in the dark room, the only light source being the moonlight that was pouring in from the window behind open blinds. Rin's fingers raked through Nitori's tousled hair, gripping the silvery strands as Ai slipped his cock into his mouth once more, the tip pressing against the inside of his soft cheek.

_"Fuck Ai- feels so good~"_ Rin moaned shamelessly as he tilted his head back, feeling his erection being sheathed in the slippery warmth of Nitori's sweet mouth. Nitori, despite the many times he had done this for Rin before, was still shaking with a mix of embarrassment and pleasure, his blue eyes squeezed shut as he sucked and licked his captain's thick cock in earnest, his own small, muffled voice coming out from his full mouth. Rin knitted his eyebrows, breathing ragged as he heard Nitori's quiet whimpers. "_Please_, whatever you do, _don't stop-_"

Suddenly, the sound of the door unlocking was prominent, the overhead light in the room flicking on as Sousuke took a step inside.

"Really? Asleep already Ri-"

It all seemed to happen in an instant, Nitori's blue eyes wide and staring at a very bewildered Sousuke, Rin's dick still deep in his mouth. Rin had what could only be described as pure shock written all over his face, his own mouth hanging open as he looked up at his now red faced roommate.

_"Y-Y-Yamazaki-senpai!?" _Nitori jolted up from between Rin's legs, pushing himself against the wall, his small hands coming down to cover his own bulge that had formed in his pink shorts. Rin effectively swiped the pillow that had been propping his shoulders up and shoved it over his nude bottom half, jumping up and standing in front of Sousuke.

"_Sousuke!_ Y-You should knock before just barging in a room like this!" Rin babbled out, his face hotter than ever as he yelled at his roommate.

"Why should I have to knock on my own door before entering?" Sousuke logically questioned, bringing his hand up to cover across his mouth as he blushed wildly, turning his gaze away from Rin and down to Nitori, who was still huddled up against the wall on the bottom half of the bunk beds. The black haired teen's eyes widened, seeing the youngest of the three shaking, his big innocent eyes beginning to well up with tears. Seeing this sparked something inside Sousuke, feeling a bit of guilt for causing such anxiety for Nitori, but something else entirely beginning to take him over.

"I didn't mean to interrupt you guys like that but..." Sousuke dropped his duffle bag onto the floor and moved forward, placing a heavy knee onto the edge of the mattress, ducking underneath the top bunk and bringing his face inches from Nitori's. "..._what were you in the middle of doing?_" Sousuke brought his hand forward, his thumb swiping over the saliva that was still smeared across Nitori's quivering lips. The silver haired boy whimpered, his cheeks glowing red as he snapped his eyes shut, the contact from Sousuke's finger making a shiver run through his body.

"_Oi_, Sousuke, what are you doing to him?!" Rin spat out angrily, actually being more embarrassed and confused than mad.

"I'm just asking a question." Sousuke turned to face Rin as he retorted, then looked back at the still shaking Nitori. "_Nitori, what were you just doing to Rin?"_ Sousuke asked in a deep whisper, inching dangerously close to his younger teammate.

Nitori kept his eyes tightly shut, unable to answer Sousuke, the overwhelming shame of being caught doing something so lewd making him want to curl up into a ball and die. After a few moments of waiting, Ai still stayed quiet. Sousuke grew impatient.

_"Is your mouth really so good that you can make your captain blush like this?" _Sousuke asked Nitori as he hovered over his smaller frame, their faces mere centimeters apart now. Rin was swallowing down a knot that had formed in his throat, finding it hard to look away from the scene before him.

Before Nitori even had the chance to respond to his disconcerting question, Sousuke's lips were suddenly pressing softly against his own. Nitori's eyes shot open, feeling his heart begin to race as his dark haired senpai began to part his mouth, sliding his tongue inside to slip against his. _"Y-Yamazaki-senpai~?" _The underclassman mewled out, feeling Sousuke's hands begin to move his wrists, exposing the large bulge in the front of Ai's shorts.

"Sousuke?!" Rin finally cried out, leaping forward onto the bed in attempt to pull the two apart. When Rin shoved Sousuke back and away from the trembling Nitori, a string of sticky saliva dripped down the tallest boy's bottom lip, making Rin's breath catch in his throat.

_"Your taste was still on Nitori's tongue...Rin," _Sousuke licked across his puffed lip, light blue eyes staring into Rin's wide and flustered ones.

"S-Sousuke...what has gotten into you?" Rin blushed deeply, gripping the pillow tightly against his lower half once more. Sousuke's eyebrow quirked up, a smirk playing on his lips as he reached over with one hand to grip Nitori's wrist, the other coming forward to grasp at the pillow.

"Do you mind if I _join you?_" The black haired teen questioned with a sensual expression, pulling Nitori away from the wall and flush against his chest and at the same time pushing the pillow away from Rin's lap. Both Nitori and Rin were confused and red faced by this point, but neither could ignore the pang of arousal that jumped through them when Sousuke suggested his involvement.

Even though Nitori was completely embarrassed, he glanced at Rin, the tears in his eyes long gone as he began to lean forward once more, spreading the red head's legs again. "A-Ai...!" Rin halfheartedly protested, shutting his mouth when Nitori's lips were parting over the head of his cock once more. Rin took in a sharp breath as he felt a wet tongue slide down the underside of his dick, Nitori's full lips sucking him off once again.

"_Mmm-_ I guess that means I'm welcome to join in..." Sousuke leaned back, eyeing Nitori's mouth as he stretched his arms, slipping his jacket off, letting it fall to the floor. Before Rin could object to his roommates comment, he was gasping, his pupils dilating as Sousuke had tilted forward, palm cupping against his balls, his tongue sliding against the base of Rin's cock.

Nitori's eyes popped open at the wet feeling of Sousuke's tongue against his lips, the youngest teen bringing his mouth completely off of Rin's erection. "Yamazaki-senpai, you-"

"_Let's make Rin feel good together..." _Sousuke glanced over to Nitori's rosy face as he smiled, pecking the silver haired teen on the lips before continuing his work on Rin's cock. Ai swallowed dryly as he watched Sousuke drag his tongue up the length of Rin's dick, his own cock pulsing beneath his pink pants.

"Okay g-guys...alright n-now cut it ou- _ahhh~!_" Rin moaned out loudly as he suddenly felt two tongues caressing his length, Nitori's bashful lips kissing against the tip while Sousuke sucked and licked underneath. "Y-y-you guys...I- _ohh fuck_- okay e-enough _m-messing around..._" Rin spoke through gasps, watching his two teammate's tongues connect and push together as they breathed around his cock. Then, Sousuke suddenly came off.

"Why are you protesting Rin?" Sousuke spoke out, leaning up and scooting further onto the bed. Rin's mouth was agape, his eyebrows turned up as Nitori was now pushing his dick against the back of his slick throat. "Could it be that _you_ want something to do with _your mouth too_?" Sousuke was now moving back to stand at the side of the bunk beds, his hands reaching to push his sweatpants down past his thighs. Rin was crying out softly now as Nitori began to suck on him sloppily, his half lidded eyes now staring up at Sousuke's exposed cock.

_"S-Sousuke...N-Nitori" _Rin whined out, blushing madly as Sousuke moved forward, sliding his cock into the red head's open mouth. _"Mphm~" _Rin moaned around his roommate's thick length, saliva beginning to drip down his chin as Sousuke began to slowly thrust in and out of his already swollen lips. The combined sensation of Nitori sucking him off and Sousuke's cock filling up his mouth was proving to be too much for Rin, his length beginning to twitch in Nitori's throat. Sensing that his upperclassman was about to release, Nitori slid off his his length, not wanting everything that was happening to end just yet.

"_R-Rin-senpai,_ not just yet..._okay?_" Nitori sheepishly said, hearing a groan come from Rin's mouth as he swallowed Sousuke. The silver haired boy got up from the bed to stand next to Sousuke, bashfully hooking his thumbs into his pink shorts and sliding them down. Both Sousuke and Rin glanced down, getting an eyeful as Nitori stood before them completely naked.

"Nitori...you're actually pretty cute," Sousuke complimented, reaching down and smoothing his palm down Nitori's bare abdomen, circling his hand around his neglected cock.

"_Ngh~!_" Nitori whimpered, letting his teeth bite against his lower lip. He had never let anyone but Rin touch him there before.

Sousuke turned his attention back to Rin, who was staring at Nitori's cock while he licked the underside of Sousuke's hungrily. The dark haired teen noticed this, suddenly reaching around to Nitori's back and pushing him forward so that the two were now side by side. _"Do you want Rin to taste you just like you tasted him?" _Sousuke teased, pulling his length away from Rin's dripping mouth. Nitori blinked down at the sight of his beloved senpai, completely vulnerable and giving an expression that was nothing but lust.

"D-do you want to taste me _senpai?_" The blue eyed boy asked cutely, a small smile playing on Nitori's nervous lips. Rin stared up at his underclassman, his heart beating out of his chest as he closed his ruby eyes, coming forward to slide Nitori into his mouth for the first time.

Ai gasped, his legs suddenly becoming weak as he moved his hands forward to slide through Rin's long red hair. This was something he had never felt before. Nitori had always been the one to service Rin- no questions asked, because in all honesty, he _really _wanted to. But now as Nitori moaned quietly, the sensation of Rin's sharp teeth lightly dragging down the length of his slick cock with every soft thrust into his mouth was a feeling he never wanted to end.

Suddenly and without warning, both Rin and Nitori jolted, the unexpected feeling of Sousuke's wet fingers sliding against their holes jarring them from their moment.

"_Y-Yamazaki-senpai?!_ What are you d-doing?!" Nitori blurted out, feeling the tallest team member's middle finger poking at his virgin entrance. Rin also seemed to be panicking, Sousuke also pushing up against his untouched area.

"You two haven't had sex with each other yet?" Sousuke simply asked, giving them a nonchalant look. Both Nitori and Rin looked at each other with blushing faces, then back to Sousuke, shaking their heads.

* * *

><p>The three Samezuka students couldn't keep track of how long it had been since this whole thing started. To them, it felt like it had been going on for hours, but they surely were not complaining in the slightest.<p>

"Are you ready?" Sousuke asked with a heavy breath, leaning back fully onto the floor of their room, all of his clothes discarded. Rin was on top of Sousuke now, his roommate's large hands gripping him by the hips, holding him over his ready and waiting cock. The red head was sweating already, the combination of nervousness and pure lust raking through his body at the moment proving too much to handle. Nitori stood in front of his two teammates, biting his lip and lazily stroking his length as he watched them.

After a long moment of mustering up all of his courage, Rin finally squeezed his eyes shut. "Okay...I'm ready-" He breathed out. Even though Sousuke had prepared both he and Nitori with his fingers, Rin was still scared out of his mind.

Would it still be painful? Would it feel great as soon as he was in? What would loosing his virginity feel like? And then, without time for Rin to mull it over in his mind any longer, it was happening. Sousuke was lowering him down, pushing his cock into Rin's tight ring of muscle.

_"Ngh...ahhh- o-oh my God~" _Rin let his mouth hang open, his red eyes wide as Sousuke slid all the way in, burying himself to the hilt inside of his childhood friend. Sousuke grunted softly, gritting his teeth and keeping his composure as well as he could. He had never felt something so _electrically tight._ He honestly didn't know how much longer he could hold off.

"Are you okay Rin-senpai?" Nitori leaned forward, placing a gentle kiss against the front of Rin's outstretched neck, wrapping his arms around his former roommate's shoulders, comforting him as he shook with what could either be pain or pleasure. Nitori waited patiently for an answer.

"_Y-Yes...so good..._" Rin finally moaned out, his mouth quivering as Sousuke gripped his toned waist even tighter. Nitori gulped down, letting out a small breath as he nodded, positioning himself over Rin's cock. Slowly but surely, Ai began to lower himself just as Rin did, and was suddenly being filled by his captain's length. Rin cried out again, tears beginning to well in the corners of his eyes.

_"S-Senpai~!" _Nitori was calling out already, not even halfway down on Rin's cock as he wrapped his slender legs around the red head's waist. "_Oh-oh my gosh-M-Matsuoka-senpai, you- you're all the way inside of me~!" _Ai began to moan girlishly, making Rin, and even Sousuke blush.

"_Heh_, have you suddenly turned into a sex maniac Ai-kun?" Sousuke teased the youngest boy, not struggling in the slightest to hold both of their weight up. Nitori just continued to mewl, beginning to bounce up and down slowly on Rin's cock without warning. Sousuke's breath hitched as he realized that the pulses from Nitori's bounding were pushing his cock deeper into Rin's ass.

The room began to be filled with deep moans and whining breaths as Sousuke began to thrust upward, holding Rin in place while he slid his cock in and out of his tight hole. Rin was grabbing for anything he could hold onto and settled for the metal rod holding the bunk beds together, trying to keep himself in balance as Nitori rode him and Sousuke plowed into him. But suddenly the red head was being pushed forward, the result of Sousuke sitting up and shoving everyone into the opposite position.

_"Ahh, mph- Yamazaki-senpai..." _Nitori cried out between moans, his back now against the cold floor with Rin hovering over him, his cock pushing into him deeper than ever before. Nitori could feel his eyes begin to water, his mouth drooling as Rin's tip hit against the bundle of nerves inside of him over and over, Sousuke brutally fucking into Rin's ass and causing a ripple effect. "_I-I'm about to..._" Ai could barely speak as Rin peered down at him with weak and wet eyes, the silver haired boy's cum spilling all over his own chest. _"R-Rin~" _

The sweet sound of Nitori calling his name as he orgasmed was all Rin needed to set him over the edge, giving one last thrust into his underclassman's ass, reaching his own release inside of Ai. Nitori whimpered as he felt himself being filled up with the hot liquid, Rin falling onto him to give him a sloppy, tongue heavy kiss.

Sousuke watched as Nitori and Rin made out, moaning out loudly as he saw Rin lick up a bit of Nitori's orgasm that had dripped into the crevice of his collarbone. Squeezing tight against Rin's lean hips one last time, Sousuke too succumbed to the waves of pleasure coursing through his body, pulling out of his roommate's ass and squirting himself all over Rin's shaking thighs.

**_~Weeks Later~_**

"Aweh! You guys are _always_ going off together after practice nowadays!" Momotarou whined, tugging on Sousuke's jacket as he, Rin, and Nitori were heading off from an exhausting day of swim practice. Nitori's cheeks colored a bit, looking away from his sporadic roommate's curious and frustrated stare. "C'mon guys! What are you all doing together?!"

"Extra physical training." Rin simply put, patting Momo on his messy orange mop of hair.

"I want to train with you guys! Please! Please please pleassssee!" Momo pleaded, throwing his arms around Rin's neck.

Sousuke stopped in his tracks, effectively making the whole group come to a halt behind him. Cocking his head back a little, a visible, crooked smile was seen playing on his lips.

_"Would you like to join us?"_


End file.
